New disazo dye.



UNITED STATES PATENT @EFTCE.

OSCAR GUNTHER AND LEOPOLD HESSE, OF ELBERFELD, GERMANY, ASSIGNORS TO FAR- BENFABRIKEN VORM. FRIEDR. BAYER & (30., OF ELBERFELD, GERMANY, A CORPORA- TION OF GERMANY.

T 0 all whom it may concern:

Be it known that we, OSCAR GiiNTHER and LEOPOLD Hnssn, doctors of philosophy,

chemists, citizens of the German Empire, residing at Elberfeld, Germany, Kingdom of Prussia, have invented new and useful Improvements in New Disazo Dyes, of which the following is a specification.

This invention relates to the manufacture and production of new disazodyestuffs dyeing cotton from violet to blue shades remarkable for their fastness to light. They are obtained by first producing intermediate compounds from the diazo compounds of the sulfurous acid ester of 1.8-aminonaphthol with suitable amins to produce the intermediate compounds, eliminating the sulfurous acid residue from these intermediate compounds, diazotizing them and combining the thus produced diazoazo compounds with 2-amino- 5-napl1thol-7-1nono-sulfonic acid.

The new dyestuffs are in the shape of their alkaline salts dark powders easily soluble in water. Upon reduction with stannous chlorid and hydrochloric acid the dyestuffs are decomposed 1.8-aminonaphthol, a diamin and 2.6-diamino-5-naphthol7-sulfonic acid are formed.

In order to carry out this process one can 6. g. proceed as follows, the parts being by weight: 223 parts of the sulfurous acid ester of 1.8-aminonaphthol are dissolved in water and 125 parts of concentrated hydrochloric acid are added thereto. The sulfurous acid ester is then diazotized with 69 parts of sodium nitrite at 0 C. and the diazo compound is added to an aqueous solution of 187.5 parts of the hydrochlorid of cresidin 170 parts of crystallized sodium acetate are gradually introduced into the mixture. The product of the reaction is acidulated with hydrochloric acid and the intermediate compound is precipitated by the addition of common salt. From the resultin azodye stuff the sulfurous acid residue is e iminated by dissolving the ester in an excess of caustic soda and by boiling the solution for some time. The product of the reaction is acidulated with hydrochloric acid, filtered off, stirred up with water and the aminoazo Specification of Letters Patent.

Application filed February 19, 1908.

' NEW DISAZO DYE.

Patented Sept. 8, 1908.

Serial No. 416,783.

compound is after cooling diazotized with 69 parts of sodium nitrite. The diazo compound is then introduced into a solution of 238 parts of 2-amino-5-naphthol-7-sulfonic acid to which sufficient sodium carbonate has been added to maintain the mixture alkaline even after the whole of the diazo compound has been added. The dyestul'f is salted out, pressed and dried. It is, after being dried and pulverized, in the shape of its sodium salt a dark owder which is solublein water with a b uish-violet color and which is soluble in, concentrated sulfuric acid with a bluish-violet color. By reduction with stannous chlorid and hydrochloric acid 1 .8'-arninonaphthol, l-methyl-2 5-diamino-4- ethoxybenzene and 2.6-diamino5-naphthol 7 -sulfonic acid areobtained. The new dyestuff dyes cotton blue shades.

The above described process is carried out in an analogous manner on using other suitable amins: to produce the intermediate compounds capable of being diazotized, such as alpha-naphthylamin, para-xylidin, metatoluidin, para acetylamino ortho toluidin, para acetylamino ortho anisidin, 1 naphthylamin-6 or 7 -sulfonic acid etc.

Having now described our invention and in what manner the same is to be performed, what we claim as new and desire to secure by Letters Patent is I 1. The herein described new azo-dyestuffs obtainable from sulfurous acid ester of 1.8-

' aminonaphthol, amins and with 2-amino-5- napl1thol-7-sulfonic acid, which dyestuffs are, after being dried and pulverized, in the shape of their alkaline salts dark powders soluble in water, soluble in concentrated sulfuric acid with from a red to violet to blue color; yielding up on reduction with stannous chlorid and hydrochloric acid 1 .S-aminonaphthol, a diamin and 2.6-diamino-5-naphthol-7sulfonic acid and dyeing cotton from violet to blue shades, substantially as hereinbefore de,

scribed.

2. The herein described new azo-dyestuff, obtainable from sulfurous acid ester of 1.8- aminonaphthol, cresidin and with 2-amino- 5-naphthol-7-sulfonic acid, which dyestuff is, after being dried and pulverized, in the shape of its sodium salt a dark powder soluble in waterwith a bluish-violet color and soluble in our hands in the presence of two subscribing concentrated sulfuric acid with a bluishviolet 001011;; yiglding hupon 1iljductiondwith Witnesses. stannous c lori and ydroc oric aci 1.8- aminonaphthol, 1 methyl 2.5 diamino 4 g ethoxybenzene and 2.6-diamino-5-naphth0l- 7-sulf0nic acid and dyeingcottonblue shades, Witnesses: substantially as hereinbefore described. OTTO K6NIG,

In testimony whereof We have hereunto set WM. WASHINGTON BRUNSWICK. 

